1. Field of the Invention:
This invention relates to a soil stabilization process. In this invention the soil particles comprising the soil surfaces to be stabilized are contacted or treated with an aqueous solution of an alkali metal silicate, such as sodium silicate, and a carbonate reactant or gelling agent selected from the group consisting of an alkylene carbonate, a polyester polycarbonate and mixtures thereof.
In another aspect this invention relates to soil stabilized by admixture with (1) an aqueous solution of an alkali metal silicate and (2) the previously described carbonate reactant.
The process of this invention is also a useful method for dust control or abatement on roads, construction sites, etc. Additionally, this process is suitable for use as a dust control method in which exposed mine surfaces are contacted or treated with the previously-described aqueous solution of an alkali metal silicate and the alkylene carbonate or polyester carbonate thereby coating the mine surfaces and lessening the possibility of dust explosions such as in coal mines.
2. Prior Art:
Silicate-based compositions useful for binding particulate matter such as soil particles are well known in the art and a number of processes in which silicate-based binder compositions suitable for use in preparing molds for metal castings have been described in the literature.
U.S. Pat. No. 4,416,694 to Stevenson et al., discloses foundry sand compositions made from a foundry sand, an aqueous sodium silicate binder and an alkylene carbonate which are used to form molds and/or cores in metal casting. The foundry sand in the foundry sand compositions disclosed by Stevenson et al., is reclaimed after the mold or core has served its purpose in metal casting.
U.S. Pat. No. 4,267,120 to Cuscurida et al., is directed to polyester polycarbonates of the type used in the practice of the present invention and to methods by which they can be prepared. Cuscurida et al., teach that the polyester polycarbonates can be used in making polymer foams including polyurethane polymers and polyisocyanurate polymers.
U.S. Pat. No. 4,359,507 to Gaul et al., discloses an adhesive binder composition for the preparation of lignocellulosic composite molded articles made from organic polyisocyanates and a liquid mixture of either ethylene carbonate or propylene carbonate with lignin and other appropriate ligno-cellulosic materials.
U.S. Pat. No. 4,773,466 to Cannarsa et al., is directed to the evaporative casting of molten metals using copolymer polycarbonates prepared from cyclohexene oxide, cyclopentene oxide, heptene oxide or isobutylene oxide and carbon monoxide.
U.S. Pat. No. 5,059,247 to Crawford et al., teaches a foundry sand composition that is self-hardening after a working life of about 10-20 minutes composed of a foundry sand, a sodium silicate binder and a specifically defined polyester polycarbonate hardener.
U.S. Pat. No. 1,827,238 to Joosten describes a process for solidifying permeable rock, loosely spread masses, etc. in which silicic acid is introduced into the mass followed by the introduction of carbon dioxide thus integrating and solidifying the treated mass.
U.S. Pat. No. 2,968,572 to Peeler, Jr. teaches a process of soil stabilization in which the soil is contacted with a single liquid mixture comprising an aqueous alkali metal silicate, an amide, such as formamide and a metal salt such as sodium aluminate thereby forming a water-insoluble gel.
U.S. Pat. No. 4,043,830 to Suzuki discloses a process for consolidation of poor quality soil by injecting hardeners comprising, for example, a mixture of water and a gelling agent and a water glass aqueous solution containing a gelling agent such as ethylene glycol diacetate.
U.S. Pat. No. 4,056,937 to Suzuki teaches a soil consolidation process in which a hardener comprising an aqueous solution of water glass and an acidic reactant, such as phosphoric acid, is injected into the soil thereby solidifying the treated soil.
U.S. Pat. No. 4,607,066 to Barry et al., discloses a process for coating geological formations and mine stoppings by applying to those substrates an aqueous sealant composition comprising a watersoluble or water dispersible polymeric binder, filter material and water and allowing the composition to dry to form an air flow resistant coating on the substrates.
U.S. Pat. No. 4,642,196 to Yah teaches a method and composition for controlling dust occurring in the production, handling, transport and storing of coal which includes applying such as by spraying an aqueous solution of a gelatinized starch.
U.S. Pat. No. 4,983,218 to Mascioli discloses a composition and method for hardening an alkali metal silicate solution using blends of alkylene diols, polyoxyalkylene glycols or hydroxyalkyl ethers. The hardened alkali metal silicate compositions are useful as binders in the preparation of foundry molds or in other applications requiring agglomeration of particulate matter.